Textiles are usually formed in a neutral color and then dyed into a final color for sale. To dye the fabrics so that the fabrics have a uniform color of the material throughout, it is important to apply the amount of dye needed to dye the textile, but not to saturate the textile with extra dye. Several applicators which can perform this function have been developed for dyeing textiles.
One type of applicator consists of an elongate tube or cylinder having a circular cross-section and including a number of perforations along its top. These perforations are called "perforated slots" in the industry. The dye applicator is designed such that a textile or carpet may run along one side of the elongate cylinder against the perforated slot. The textile is held in position against the slots by way of a backing device, such as a roll, bladder, or any other drawing or tensioning device, to maintain a seal between the textile and the applicator.
The perforated slot applicators generally introduce dye at a uniform pressure into the side of the cylinder opposite the perforated slots. The pressure of the dye is preferably adequate to push the amount of dye through the perforated slots needed to dye the textile, but not saturate the textile with the dye.
The perforated slot applicators usually have a uniform length, such as twelve feet. This length is ideal for a textile specimen which is the entire length of the applicator, or twelve feet wide. Problems occur when the applicator is used to dye a specimen which is narrower than the length of the applicator, such as a textile which is six feet wide. The textile to be dyed effects a seal on the perforated slots it covers, causing a pressure differential between the covered and uncovered perforated slots. Because the pressure differential between the uncovered perforated slots and the covered perforated slots is so great, the dye tends to flow out of the uncovered slots, instead of into the textile, and therefore is wasted and can contaminate the surroundings.
One way that this problem has been dealt with in the past is to provide a reciprocating plug within the elongate cylinder. This plug moves along the inside of the cylinder and effects a seal at its location. The dye inlets on one side of the plug are shut off as the plug is moved such that the dye is introduced only into the opposite side of the cylinder. A problem occurs if the textile is not fed evenly along its length so that the textile moves back and forth along the elongate cylinder. In response to this, sensors have been employed to determine the ends of the textile and adjust the plug to the end. This system may also employ two of the reciprocating plugs, having complex sensors so that the edges of the fabric may be sensed and the plugs may move accordingly.
As can be understood from the foregoing, such a system is complex and can be expensive. Therefore, there is a need in the art for a simpler, more inexpensive means of supplying dye to specific regions of a cylinder on a dye applicator.